The invention relates to a double band pushbutton tuner, and more particularly to an actuator which connects a pushbutton member with a tuning slide which belongs to a selected frequency band.
A pushbutton tuner is known in which each pushbutton slide is adapted to selectively drive either one of a pair of associated tuning slides. Such tuner is often used in a two frequency band radio set. In a conventional tuner, each pushbutton slide carries an interconnecting member having a rocker arm or pin and which slides or tilts laterally in response to an operation of a band change-over switch for engagement with either one of adjacent tuning slides. At this end, each tuning slide is formed with a slot which is engaged by the interconnecting member. An actuator having a laterally moving interconnecting member is described in U.S. Pat. No. 3,722,299 issued to Knight et al. on Mar. 27, 1973. In this patent, the interconnecting member comprises a T-shaped pin, with the horizontal arm disposed within a pin guide carried by the pushbutton slide while the upstanding pin portion extends into a slot formed in a laterally shiftable plate. Thus, when the shift plate is displaced laterally, the T-shaped pin moves also laterally within the pin guide. During such movement, the upstanding end of the pin produces a force as a result of its abutting engagement with the shift plate, which force urges the pin not only in the lateral direction but also downwardly, thereby giving rise to a substantial amount of sliding friction between the pin and guide. As a consequence, a high load is applied to the shift plate which drives the pin, thereby adversely influencing on a smooth operation of the shift plate. An actuator having a tiltable interconnecting member is described, for example, in U.S. Pat. No. 3,357,264 issued to G. H. Newman on Dec. 12, 1967 and also in U.S. Pat. No. 3,415,129 issued to R. D. Stamm on Dec. 10, 1968. In these actuators, the interconnecting member is pivotally mounted on a pivot which is carried by the pushbutton slide, so that the problem of sliding friction as mentioned above does not result. However, a degree of friction occurs between the pivot and the interconnecting member, which somewhat impedes the movement of the shift plate which operates to tilt the interconnecting member. In addition, the provision of such a tiltable interconnecting member results in a complex structure, thereby requiring a time consuming assembly and repair.